Nielsen Hayden genealogy
Descendants of (Unknown wife of Bleddyn ap Cynfyn)
(Unknown wife of Bleddyn ap Cynfyn)
   └─ Efa ferch Bleddyn ap Cynfyn
    Llywelyn Eurdorchog ap Coel ap Gweirydd (Abt 1030 - ??)
       └─ Rhys ap Llywelyn Eurdorchog
       
            + Ithel ab Einudd ap Morien ap Morgeneu (Abt 1100 - ??)